Advancements in soft-lithography and microfluidics techniques have brought the idea of lab-on-a-chip technology to the forefront of modern chemical and biomedical research (McDonald et al., Electrophoresis, 21(1):27-40, 2000).
Microfluidics improves standard laboratory protocols insofar as it allows for the manipulation of volumes on the order of picoliters, and this creates a higher degree of control and minimizes the use of costly or toxic reagents. Of particular interest has been the application of droplet or digital microfluidics, which employs the use of droplet formation and manipulation in microfluidics devices (Huebner et al., Lab on a Chip, 8:1244-1254, 2008; The et al., Lab on a Chip, 8:198-220, 2008). Droplet formation allows for the encapsulation and thus isolation of specific solutes, which greatly reduces the potential for mixing or dispersion caused by velocity gradients within the channel. Also, with high monodispersity, droplet microfluidics permits precise fusion of various solutions at specific ratios using electric fields and droplet frequency synchronization (Ahn et al., Applied Physics Letters, 88(26):265106, 2006). This level of precise control and efficiency has made droplet microfluidics devices an ideal platform for genetic analyses that would otherwise require much more costly and time consuming procedures.